Agraffe



(No Model.) 2 Sheets-Sheet 1. F. SCHIMMEL & S. F. NELSON.

AGRAPFB.

.P'atentd Aug. 15, 1893.

m l. [Ul/l @ummm Y (No Model.) 2 Sheets-Sheet 2.

F, SGHIMMEL & S. P. NELSON. AGRAPFE.

No. 503,167. Patented Aug. 15, 1893.

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FRIDOLIN SCHIMMEL AND SEARICK F. NELSON, OF MINNEAPOLIS, MINNESOTA.

AG RAFFE.

SPECIFICATION forming part of Letters Patent No. 503,16*?, dated August15, 1893.

Application filed September 27, 1892. Seria1N0.447,018. (No model.)

To @ZZ whom t may concern:

Be it known that we, FEIDOLIN SCHIMMEL and SEAEICK F. NELSON, of thecity of Minneapolis, county of Hennepin, State of Minnesota, haveinvented a certain new and Imfproved Agraife, of which the following isa specification.

Our invention relates to pianos and in particular toa new and reliablemeans for exerting an even and adequate tension upon each string of apiano.

The object of the invention is to replace the old style agraffe ortension bar by one of greater simplicity and cheapness, and which by itspeculiar construction and attachment will give to a piano an evennessand softness of tone unattainable where bars of the ordinary type areemployed; and a further object which we have in view is to provide aperfect scale from one end of the key-board to the other, without theinaccuracy of pitch which exits in the pianos of the present day. Thiswe accomplish as shown in an actual piano of our construction.

Our invention consistsin general in the constructions and combinationshereinafter described and particularly pointed out in the claims, andwill be more readily understood by reference to the accompanyingdrawings, in which Figure l is a front view of a piano string board orframe of the construction embodying our invention. Fig. 2 is a sectionalview thereof on the line :nof Fig. l. Fig. 3 is an enlarged verticalsection on line a--e of Fig. l. Fig. 4: shows the agraffe or pressurebar solid with the iron frame. Fig. 5 shows a modified form of ourinvention.

In the drawings, 2 represents the iron frame of the piano placed overthe wooden back frame 3, having the pin block portion a in which are thepins 5, arranged in the usual manner so that the strings are` formed ingroups of three. For clearness a great many of the strings are left outin the drawings. The lower edge or shoulder of the pin-block opening 6in the iron frame is provided with the seat projections or parts 7,preferably three in number and equal-distances apart, like seats beingformed at the end of the open ing to receive the ends of the agraffe bar8,

which is provided with the holes for thelarge screws 9, passing throughthe iron frame into the wooden frame of the piano. The bar has a generalinclination downwardly so as to cross the strings at as nearly rightangles as possible, and has the long ogee curved form shown accuratelyin Fig. 1. The lower corner of the bar is scalloped out giving the barthe cross section and strength of an angle bar without unnecessaryweight. The back of the bar has surfaced seats to engage the surfaceprojections on the plate, which are broad and aiford a solid bearingtherefor. On the rear side of the bar and preferably ranging along theupper edge thereof is the narrow bead or edge l0, having a comparativelysharp edge to bear against the strings ll. Beneath this rim the bar isout back to remove it from contact with the strings extending beneaththe same and over the sharp bridge l2 formed integrally with the ironframe. This bridge instead of being carried along parallel with theagraffe bar departs therefrom gradually, beginning at the upper endwhere the longest strings engage it, so that at the lower right hand endthe bridge stands a considerable distance away from the agraffe barleaving a much longer length of string between the pins and the bridge.By this regular lengthening of the distances between the bridge and theagraffe bar it will be seen thata regularpress ure equal at all pointsis obtained by the bar. The purchase of the agraife bar upon the stringsbecoming' greater as a string grows shorter, until at the last shortgroup of strings, the distance between the pins and the bridge is sogreat that the movement of the bar against the same in this securedposition is very slight, the requisite tensionIupon the strings beingobtained without putting the same at too great an angle of strainbeneath the sharp rear edge of the agraffe bar. In

consequence of this construction the life of the strings is len gthened,a greater latitude of adjustment secured for obtaining the proper pitchor tone of each string. From this easy IOO of the cross section shown inFig. 5,in which the sharp edge 15 corresponding to the rib 10 of Fig 3,is arranged about midway on the back of the bar, being equally sharpwith the other and about in line with the screws. We prefer the firstconstruction, however, as we find in placing the bar upon the stringsthat the lower corner 16 of the agraffe bar (Fig. 3), strikes the seatsupon the plate in advance of the upper edge, so that the rib 10 isbrought down through a short arc of a circle; admit-` ting of a fineradjustment than can be obtained with the bar shown in Fig. 5. Both ofthese bars are of very large cross section as compared to any of thedevices before employed and combine the qualities of perfect solidityand inflexibility, with that of neatness.

In some cases where it is desired to still further rednce the cost ofconstruction, we cast the agraffe bar 18 Fig. 4 integral with the plateor frame, finishing only the sharp rib on the back of the bar and edgeof the bridge 12. One of the great advantages of either of ourconstructions is that we are enabled to exert an even tension withoutthe employment of the great number of screws now found in pianos, whichof themselves rattling in their places do much toward producing theharsh metallic sound, which we in our pianos fully avoid.

Having thus described our invention, we claim as new and desire tosecure by Letters Patent- 1. The combination, with the metal piano frameor board, of the pins and strings, agraffe bar arranged on said frame,and a bridge arranged angularly with respect to said agraife bar, beingfarthest away therefrom at the point where the shortened strings crossthe same, substantially as and for the purpose specified.

2. The combination, with the piano frame, of the single cast metalagraffe bar, provided with the continuous rib on its under side, thestrings, and the bridge 12 departing from said bar as described,and bothbeingcurvedfsubstantially as and for the purpose specified.

3. The combination with the metal piano frame and the pin block, ofabridge, the pins, the strings extending therefrom over said bridge, theseats 7 arranged upon said metal frame and an agraife consisting of asingle infiexible metal bar, having a broad and substantially fiat backprovided with an integral sharp rib 10 to engage the strings, and saidbar having the shoulders or projections 16 to rest upon said seats andfive screws extending therethrough into the seat portions substantiallyas and for the purpose specified.

In testimony whereof I have hereunto set my hand this 17th day ofSeptember, 1892.

FRIDOLIN SCHIMMEL.

In presence of H. M. LAUBENHEINER, E. C. HAMBURGHER. In testimonywhereof l have hereunto set my hand this 13th day of September, 1892.

SEARICK F. NELSON. In presence of- O. G. HAWLEY, F. S. LYON.

